­ scientists need to channel their efforts wisely and engage with the political process nationally and internationally.

“We shall need, in all fields of science, individuals with the wisdom and commitment of the

atomic scientists who founded the Bulletin,” he said.

The board of directors of the Bulletin of the Atomic Scientists said the threat of nuclear

apocalypse was now almost matched by the environmental threats posed by climate change.

“We stand at the brink of a second nuclear age. Not since the first atomic bombs were dropped on Hiroshima and Nagasaki has the world faced such perilous choices,” the board said in a statement issued yesterday.

“North Korea’s recent test of a nuclear weapon, Iran’s nuclear ambitions, a renewed US emphasis on the military utility of nuclear weapons, the failure to adequately secure nuclear materials and the continued presence of some 26,000 nuclear weapons in the United States and Russia are symptomatic of a larger failure to solve the problems posed by the most destructive technology on Earth.

“As in past deliberations, we have examined other human-made threats to civilisation. We have

concluded the dangers posed by climate change are nearly as dire as those posed by nuclear weapons. The effects may be less dramatic in the short term than the destruction that could be wrought by nuclear explosions, but over the next three to four decades climate change could cause drastic harm.”